CalcFuel Burn Calculator
Last updated: 2026-05-07
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| Flow (gal/h) | Time (h) | |
|---|---|---|
| City | 5 gal/h | 1 h |
| Suburban | 8 gal/h | 2 h |
| Highway | 10 gal/h | 2 h |
| Long haul | 15 gal/h | 3 h |
| International | 20 gal/h | 4 h |
Fuel Consumption Calculator: Plan Your Flight Fuel
The Fuel Consumption calculator determines total trip fuel, fuel burn rates, and reserve requirements for any flight. Whether you fly a single-engine piston trainer or a light business jet, accurate fuel planning is the difference between a routine flight and an emergency. This calculator helps pilots comply with regulatory fuel reserve requirements while optimizing fuel load for safety and efficiency.
You may also find the Crosswind Component Calculator, True Airspeed Calculator, and Hull Speed Calculator useful.
Aviation Fuel Planning Formula
Trip Fuel = Burn Rate × Flight Time
Total Required = Trip Fuel + Reserve + Alternate + Contingency
Fuel burn rate is typically expressed in gallons per hour (GPH) for piston aircraft or pounds per hour for turbine aircraft. Flight time is calculated from takeoff to landing, including climb, cruise, and descent segments. Reserve fuel is the amount required to reach an alternate airport after the destination plus a regulatory buffer, typically 30-45 minutes at normal cruise power.
Most aviation authorities mandate specific fuel reserves. In the US, FAR 91.151 requires VFR day flights to carry enough fuel to fly to the destination plus 30 minutes thereafter. For IFR flights, FAR 91.167 requires enough fuel to reach the destination, then to an alternate, plus 45 minutes at normal cruise. This calculator automates these regulatory requirements so you never leave the ground with insufficient fuel.
Worked Examples
Example 1: VFR Cross-Country Flight
A Cessna 172 pilot plans a 180-nautical-mile VFR cross-country flight. The aircraft burns 8.5 GPH at 75% power, cruising at 120 knots true airspeed. Estimated flight time including climb and descent is 1.8 hours.
Trip fuel: 8.5 GPH × 1.8 hours = 15.3 gallons
VFR day reserve (30 minutes): 8.5 GPH × 0.5 hours = 4.25 gallons
Startup and taxi: 0.5 gallons
Total fuel required: 15.3 + 4.25 + 0.5 = 20.05 gallons
The Cessna 172 has a usable fuel capacity of 48 gallons, so this flight is well within limits with substantial margin. The pilot should check fuel levels before each flight since fuel gauges are notoriously unreliable in light aircraft.
Example 2: IFR Business Jet Flight
A Citation CJ4 pilot plans a 700-nautical-mile IFR flight. Each engine burns 285 pounds per hour at normal cruise. Flight time is 2.3 hours. An alternate airport is required, adding 20 minutes of flying time.
Trip fuel: (285 × 2) × 2.3 = 1,311 pounds
Alternate fuel: (285 × 2) × 0.33 = 188 pounds
IFR reserve (45 minutes): (285 × 2) × 0.75 = 428 pounds
Contingency (5%): 1,311 × 0.05 = 66 pounds
Total fuel required: 1,311 + 188 + 428 + 66 = 1,993 pounds
The Citation CJ4 has a total fuel capacity of approximately 4,300 pounds, so this flight is well within limits. The pilot will load approximately 2,000 pounds for the trip, optimizing the center of gravity and minimizing unnecessary fuel weight.
Common Uses
- Pre-flight fuel planning to ensure regulatory compliance with VFR and IFR reserve requirements
- Comparing fuel efficiency across different cruise altitudes and power settings for cost savings
- Calculating maximum range and endurance for flight planning and route selection
- Determining fuel stop locations on long cross-country flights to avoid landing with low fuel
- Training student pilots on the importance of fuel management and reserve calculation
- Optimizing fuel load to balance weight and balance considerations for safe takeoff performance
Common Mistakes
- Confusing gallons per hour with pounds per hour — aviation gasoline weighs about 6 pounds per gallon and Jet-A weighs about 6.7 pounds per gallon, so using the wrong unit can significantly misstate your fuel situation
- Forgetting to include taxi, run-up, and takeoff fuel in the total — engines burn fuel on the ground too, and the run-up can consume several gallons before you ever leave the ramp
- Neglecting the effect of headwinds on flight time — a strong headwind can increase your flight time by 20-30%, consuming your reserve fuel and leaving you in a low-fuel situation
- Relying on fuel flow gauges without cross-checking against time — even calibrated fuel flow sensors can drift, and the only true measure of fuel remaining is the pre-flight visual inspection and your time-based calculation
Pro Tip
Always use the "rule of thirds" for IFR fuel planning: one-third of your fuel to the destination, one-third to the alternate, and one-third as reserve. This conservative approach provides a significant safety margin beyond regulatory minimums. In practice, if your flight to the alternate isn't needed, you land with two-thirds of your original fuel still in the tanks. This rule has saved countless pilots from low-fuel emergencies and is standard practice in many airline operations departments. When in doubt, the only good answer to "do I have enough fuel?" is "yes, with ample margin."
Frequently Asked Questions
Multiply the aircraft's fuel burn rate (gallons or liters per hour) by the estimated flight time. Then add taxi fuel, reserve fuel (typically 30-45 minutes), alternate fuel if needed, and contingency fuel (5-10% of trip fuel). This gives you the total fuel required before engine start.
Typical fuel burn rates vary widely: Cessna 172 burns about 7-9 GPH, Piaggio Baron burns 8-10 GPH, Cirrus SR22 burns 12-16 GPH, and a Beechcraft Baron burns 20-26 GPH per engine. For commercial jets, a Boeing 737 burns approximately 750-850 GPH depending on load and altitude.
Higher altitudes generally reduce fuel consumption because the air is thinner, reducing drag and allowing the engine to operate more efficiently. The optimal altitude for fuel efficiency in piston aircraft is typically around 6,000-10,000 feet MSL. Turbofan engines on jets achieve best fuel efficiency at higher altitudes around 35,000-40,000 feet.
Fuel burn rate (gallons per hour) is the actual volume of fuel consumed per hour of flight. Specific fuel consumption (SFC) is a measure of engine efficiency expressed as fuel mass per unit of thrust or power per hour. SFC allows comparison of engine efficiency across different aircraft sizes.